JP4375106B2 - Image processing device - Google Patents

Description

  The present invention relates to an image communication apparatus for performing a predetermined process such as compressing image data to be processed and filing it in a storage device via a network or outputting it to a printer device.

In recent years, image data has been standardized as, for example, a method of separating character / line drawing parts and patterns / background parts and independently compressing and coding them (ITU-T recommendation T.44 as mixed star content (hereinafter abbreviated as MRC)). Can be encoded with high compression while reducing mosquito noise that occurs when JPEG (Joint Picture Experts Group) compression is applied to image data containing mixed characters and pictures. Attracted attention in terms of. The ITU-T recommendation T.I. In 44, the method for increasing the compression rate or improving the image quality is not defined, and the specific method for the compression process is different for each implementation.
JP 2000-307867 A JP 2001-78009 A

  This ITU-T recommendation T.I. In the conventional apparatus which implements the method based on 44, the character / line drawing part and the picture / background part are usually compressed by a predetermined compression method. Further, the compression parameter is determined exclusively based on the contents of the image data. For this reason, depending on the use of the image after compression, the balance between the compression rate and the image quality may not be in a state desired by the user. For example, in general, it is desirable to increase the compression rate (in this case, the image quality is slightly degraded) when sending by e-mail, etc., and when saving as a file, the image quality is increased (in this case, the compression rate is slightly decreased) Is desirable.

  Therefore, it may be considered that the user can arbitrarily adjust the compression parameter. However, adjustment of compression parameters is not always easy.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image processing apparatus capable of controlling the compression rate in accordance with the application with an easy operation.

  The present invention for solving the problems of the above-described conventional example is an image processing apparatus, a means for accepting processing designation for image data to be processed, and separation compression based on the contents of the designated processing Based on the means for setting conditions and the set separation and compression conditions, each pixel of the image data is separated into a plurality of planes, each plane is subjected to compression processing, and the data of each plane after compression processing is included Compression processing means for generating compressed data, wherein the compressed data is subjected to the designated processing.

  Here, the designated process is a process of transferring image data to a designated transfer destination, and the separation compression condition may be set based on the designated transfer destination. The designated process may be a process of transferring image data to a designated transfer destination, and the separation and compression condition may be set based on a protocol type related to the transfer process. Furthermore, the designated process may be a process of transferring image data to a designated transfer destination, and the separation / compression condition may be set based on address information of the transfer destination.

  Further, in these, the separation / compression condition may include a condition as to whether or not to perform a limited color processing for reducing the number of colors used for at least one of the planes. Further, the number of planes to be output may be different depending on the setting of the separation condition.

  The image processing method according to an aspect of the present invention accepts designation of processing for image data to be processed, sets separation compression conditions based on the contents of the designated processing, and sets the set separation compression conditions Each pixel of the image data is separated into a plurality of planes, compression processing of each plane is performed, compressed data including data of each plane after compression processing is generated, and the compressed data is It is characterized in that it is subjected to processed processing.

  Further, a program according to another aspect of the present invention includes a procedure for accepting a processing designation for image data to be processed in a computer, and a procedure for setting a separation and compression condition based on the contents of the designated processing. Based on the set separation compression condition, each pixel of the image data is separated into a plurality of planes, each plane is subjected to compression processing, and compressed data including data of each plane after compression processing is generated And the compressed data is used for the designated processing.

  Embodiments of the present invention will be described with reference to the drawings. An image processing apparatus 1 according to an embodiment of the present invention includes a control unit 11, a storage unit 12, an operation unit 13, a display unit 14, a communication unit 15, and an input / output interface (I / F) 16. It is configured to include. Further, this image processing apparatus may be connected to the scanner 2 or the printer 3 or may be connected to another information processing apparatus via a network. The image processing apparatus 1 according to the present embodiment can be realized by a personal computer connected to a network, a multifunction machine, or the like.

  The control unit 11 can be realized by a CPU (Central Processing Unit) or the like, and operates according to a program stored in the storage unit 12. Specifically, the control unit 11 separates the image data to be processed into a plurality of planes according to the condition setting process for setting the separation compression conditions and the set separation compression conditions, and compresses each plane. Separation and compression processing is executed. In addition, the control unit 11 generates compressed data including data of each plane after the compression processing, and executes processing designated by the user for the compressed data. Specific processing contents of the control unit 11 will be described in detail later.

  The storage unit 12 includes a computer-readable recording medium that stores a program executed by the control unit 11. Specifically, the storage unit 12 includes a RAM (Random Access Memory) and a ROM (Read Only Memory).

  The operation unit 13 is a keyboard, a mouse, or the like, and outputs the content of the operation performed by the user to the control unit 11. The display unit 14 is a display that displays an image in accordance with an instruction input from the control unit 11. The communication unit 15 transmits various data such as compressed data (image data after compression processing) to a designated destination via a network in accordance with an instruction input from the control unit 11. Further, the communication unit 15 receives various data received via the network and outputs the data to the control unit 11.

  The input / output I / F 16 is, for example, a USB (Universal Serial Bus) interface or the like, and is connected to the scanner 2 and the printer 3, and outputs image data read by the scanner 2 to the control unit 11. Further, the image data is transferred to the printer 3 in accordance with an instruction input from the control unit 11.

  Here, specific contents of the program executed by the control unit 11 will be described. The program executed by the control unit 11 includes a separation / compression unit 21, an information acquisition unit 22, and an output unit 23, as functionally shown in FIG. In the present embodiment, the image data to be processed is acquired via, for example, a network, or read and acquired by the scanner 2 and stored in the storage unit 12.

  The separation / compression unit 21 separates the image data into a plurality of planes. In the present embodiment, the image data is basically separated into a plurality of planes including at least two types of planes relating to the character / line drawing portion and planes relating to the design / background portion. The separation / compression unit 21 compresses the data of the generated plurality of planes based on the set separation / compression condition, synthesizes the data after the compression processing, generates compressed data, and outputs the output unit 23. Output to. What is characteristic in the present embodiment is that processing such as further separation of characters and line drawings according to separation and compression conditions, and further separation of a photograph and a solid background is performed. The specific processing contents of the separation / compression unit 21 will be described later.

  The information acquisition unit 22 acquires the processing content designated by the user for the image data to be processed, sets the separation / compression condition based on the acquired processing content, and outputs the separation / compression condition to the separation / compression unit 21. . The output unit 23 generates the compressed data output from the separation / compression unit 21 as one file, and outputs the file for use in processing designated by the user.

  Here, the specific content of the separation compression unit 21 will be described. As shown functionally in FIG. 3, the separation and compression unit 21 includes a binarization unit 31, an isolated point removal unit 32, a multiplexer 33, a hole filling processing unit 34, an accumulation unit 35, and a character area detection unit. 36, a character representative color determination unit 37, a smoothing processing unit 38, and a selection unit 39.

  The binarization unit 31 sets, for each pixel included in the image data to be processed, “white” that the brightness of each pixel value exceeds a threshold value, “black” or the like that does not exceed the threshold value, and the like. It binarizes and outputs as image data (binarized data) including the binarized pixels.

  Specifically, the binarization unit 31 sets the binarization threshold according to the local characteristics of the image data in order to extract characters in the colored background, characters included in the photograph portion, and the like. (E.g., based on the moving average method, when the luminance value of the pixel of interest is higher than the average luminance value of the surrounding pixels by a certain level or more, the pixel is set to “black” (significant pixel). This is called a valuation method. However, the present invention is not limited to this, and simple binarization processing may be used in which the binarization threshold is constant for the entire image data.

  The isolated point removing unit 32 removes a pixel block having a predetermined size or less from the binarized data as an isolated point. An example of the processing of the isolated point removal unit will be described with reference to FIG. The isolated point removing unit 32 sets each pixel of the binarized data as a pixel of interest in, for example, a scan line order (an order in which scanning is repeated from left to right of the uppermost line, to the next line, and from left to right). The following processing is performed while selecting. Here, for example, when the size of an isolated point to be removed is 3 × 3 pixels or less, a window having a size of 5 × 5 centering on the pixel of interest is defined, and a pixel block including the pixel of interest (here, Since significant pixels are illustrated in black, it is determined whether or not the size of this pixel block is 3 × 3 or less. In the examples of FIG. 4B, FIG. 4C, and FIG. 4E, the entire pixel block including the target pixel is surrounded by at least one white pixel, so that the pixel block including the target pixel is isolated. Judged to be a point. In the case of FIG. 4D, a pixel block of 3 × 3 pixels appears in the window. However, since the color of the pixel outside the window is unknown, it is determined at this stage whether or not it is an isolated point. I can't. In FIG. 4 (f) and FIG. 4 (e), since a pixel block having a size exceeding 3 × 3 appears in the window, it is determined that the pixel in the window including the target pixel is not an isolated point.

  The isolated point removal unit 32 sets the pixels constituting the pixel block determined to be an isolated point as white pixels as non-significant pixels. Thus, for example, when the halftone image is binarized, the halftone portion becomes a significant pixel, and the binarized image can be prevented from being handled as character / line drawing shape data as it is.

  Instead of the isolated point removal method as described above, or together with this isolated point removal method, a known layout analysis process (process for detecting the arrangement of character strings) is performed on the binarized data to obtain a character. It is also possible to detect an area estimated to contain the image data and to select image data consisting of significant pixels in the area (character area) as selection data.

  That is, by the processing of the binarization unit 31 and the isolated point removal unit 32, the pixels constituting the character / line image are detected, and image data including only the pixels is output as selection data.

  The multiplexer 33 outputs, as foreground data, image data obtained by extracting pixels that are significant pixels in the selection data from the pixels of the image data to be processed. In addition, image data obtained by extracting pixels related to pixels that are not significant pixels in the selection data among the pixels of the image data to be processed is output as background data. Specifically, as shown in FIG. 5A, for image data including a character string “JAPAN” and a map of Japan, first, selection data as shown in FIG. In general, since the pixels constituting the pattern portion have a smaller brightness difference than the surrounding pixels, this selection data is data including a character portion).

  The foreground data obtained by extracting the part specified by the selection data from the original image data is as shown in FIG. In FIG. 5, the difference in color is shown with different hatching. On the other hand, the background data is as shown in FIG. At this time, in the image data of FIG. 5D, the pixel value at the position where the character “JAPAN” was found is not set, so to say “hole”.

  The hole filling processing unit 34 is a process of setting a hole portion in the background data where the pixel value is not set to the peripheral pixel value. Specifically, each pixel of the background data is scanned in raster scan order, and when the selection data transitions from a non-significant pixel to a significant pixel, the immediately preceding pixel value is stored, and the stored pixel value Is set as the pixel of the hole.

  The storage unit 35 stores the selection data, foreground data, and background data after the hole filling process in the storage unit 12 and holds them. By storing the data in the middle of the separation process in the storage unit 12 in this way, it is not necessary to process the image data again when it is desired to change the separation compression condition later.

  The character area detection unit 36 reads the selection data from the storage unit 12, detects a pixel block on the selection data by a labeling process or the like, and defines a circumscribed rectangle for each pixel block corresponding to each given label. . Then, information on the defined circumscribed rectangle (coordinate information demarcating the circumscribed rectangle) is output to the selection unit 39 and also output to the character representative color determination unit 37.

  The character representative color determination unit 37 examines pixel values in the foreground data corresponding to each circumscribed rectangle for each defined character / line drawing, generates a pixel value histogram (occurrence frequency), and has the highest value in this histogram. One pixel value that appears at a frequency or at least one pixel value that appears at a frequency exceeding a predetermined threshold value (for example, 1/3 of the number of pixels in the target basic rectangle) is determined as a representative pixel value. Then, the representative pixel value determined using the pixels in the rectangle is stored in the storage unit 12 as a representative pixel value database in association with the identifier issued to each rectangle.

  Further, the character representative color determination unit 37 groups the representative pixel values stored in the representative pixel value database for each color determined to be the same. Specifically, among representative pixel values stored in the representative pixel value database, a representative pixel value that has not yet been grouped is set as a representative pixel value of interest, and is a representative pixel value different from the representative pixel value of interest, Representative pixel values that are not yet grouped are sequentially selected as comparison pixel values. If there is a comparison pixel value that can be determined to be the same color as the representative pixel value of interest (for example, a distance in the color space is less than a predetermined distance threshold), the at least one comparison pixel value and The representative pixel value is determined as one group. Then, a rectangular identifier associated with the grouped representative pixel value is extracted from the representative pixel value database, a list of rectangular identifiers is generated, and the one is determined based on the representative pixel value of interest and the comparison pixel value. One group representative pixel value is determined. Further, the character representative color determination unit 37 issues a unique group identifier, and associates the group identifier, the group representative pixel value, and the generated list of rectangular identifiers as the same color region information database, and stores the storage unit 12. To store. Note that the group representative pixel value determination method may be, for example, a pixel value of a statistical calculation result (for example, an average) between a target representative pixel value and a comparison pixel value determined to be the same.

  On the other hand, when there is no comparison pixel value that can be determined to be the same color as the representative pixel value of interest, a group including only the representative pixel value of interest is generated. In this case, the identifier of the basic rectangle associated with the target representative pixel value is extracted from the representative pixel value database, and the target representative pixel value is determined as it is as the group representative pixel value. A unique group identifier is issued, and the group identifier, the group representative pixel value, and the generated rectangular identifier are associated with each other and stored in the storage unit 12 as the same color area information database.

  In this way, the character representative color determining unit 37 defines, for each grouped representative pixel value (group representative pixel value), the representative pixel value (group representative pixel value) and an area corresponding to the representative pixel value (here. Then, the same color area information including information associated with the area identifier) is generated and stored in the storage unit 12 as the same color area information database.

  Further, the character representative color determination unit 37 defines a rectangle that further circumscribes the area associated with each group as a group rectangle. In this example, the circumscribed rectangle for each character / line drawing is extracted from the entire selection data. However, layout analysis processing is performed on the selection data, and each layout element (character string area) extracted by the layout analysis processing is described. The above processing may be performed.

  According to this, as shown in FIG. 6, when two layout elements are defined, a rectangular region including them is defined for each character determined to have the same color inside. That is, rectangles X1 and X2 for each group are defined from the rectangle X, and rectangles Y1 and Y2 for each group are defined from the rectangle Y. In FIG. 6, it is assumed that the character “K” is black, the character “R” is red, and the character “B” is blue.

  The character representative color determination unit 37 outputs the defined group rectangle and the representative pixel value (group representative pixel value) associated with the group rectangle to the selection unit 39.

  The smoothing processing unit 38 is a process of setting a hole portion in the foreground data, for which the pixel value is not set, to the peripheral pixel value. Specifically, each pixel of the foreground data is scanned in raster scan order, and when the selection data transitions from a significant pixel to an insignificant pixel, the pixel value immediately before that is stored, and the stored pixel value Is set as the pixel of the hole.

  That is, when the operations in the hole filling processing unit 34 and the smoothing processing unit 38 are schematically shown, as shown in FIG. 7A, the input data is read from D1 to D32 in the scan order, and the selection data (FIG. 7) is displayed. When (b)) is a significant pixel (foreground) and an insignificant pixel (background), foreground data that has undergone smoothing processing is initially not set to a pixel value, as shown in FIG. 7C. (“00”), while the selected data is “foreground”, the input data itself is used. When the selected data becomes “background”, the data values immediately before the selected data are continuously arranged.

  Also, as a result of the hole filling process being performed on the background data, as shown in FIG. 7D, the input data itself is the same as long as the selection data is “background”. When the selected data becomes “foreground”, the data values immediately before the selected data are continuously arranged.

  The selection unit 39 receives input of information defining a rectangle for each character / line drawing from the character region detection unit 36, receives a group rectangle defined from the character representative color determination unit 37, and a representative pixel value ( Group representative pixel values) and foreground data after smoothing processing from the smoothing processing unit 38. The selection unit 39 reads selection data and background data from the storage unit 12.

  The selection unit 39 selectively outputs each piece of information based on the separation and compression condition input from the information acquisition unit 22.

  Specifically, the information acquisition unit 22 receives information about the transfer destination of the image data from the user, and sets the separation compression condition that is predetermined for each transfer destination and stored in the storage unit 12. Here, the transfer destination is, for example, information indicating the type of output destination (printer, storage unit 12 or the like), an e-mail address (corresponding to an example of address information of the present invention), a network address of the transfer destination (also this It corresponds to an example of address information of the present invention).

  The separation / compression condition may be stored in the storage unit 12 in association with the type of protocol used for transfer to the transfer destination. Here, the type of protocol is different from LPR (a type of protocol used for transfer to a printer), SMTP (a protocol used for data transfer using an e-mail system such as e-mail and Internet FAX), and the like.

  In the present embodiment, there are a high image quality mode and a high compression mode for handling characters and line drawings. That is, in the high compression mode, the selection unit 39 selectively uses a character / line drawing separated for each group that is identified as the same color (information output by the character representative color determination unit 37). The selected data is compressed by a method such as MMR or JBIG, and information for defining a rectangle for each group and group representative color information associated with the group are output.

  In the high image quality mode, the selection unit 39 selectively uses the selected data and the smoothed foreground data, performs MMR compression on the selected data, and multilevel reversible compression (color color) on the smoothed foreground data. Data including information is reversibly compressed) or JPEG compressed.

  In this way, in the high compression mode, the number of colors used for the text / line drawing plane is reduced and the limited color processing is performed, so that the original color is changed instead of improving the compression rate. The image quality generally deteriorates. Note that the selection unit 39 outputs the background data after JPEG compression.

  Normally, when sending by e-mail, there is a limitation on transfer capacity in the e-mail system, so it is preferable to use high compression mode data. In transferring to a printer, storage unit 12 (disk device, etc.), file server, etc., it is preferable to use high-quality mode data in consideration of later reuse. For this reason, for example, in the SMTP protocol representing the transfer in the e-mail system, the separation compression condition for setting the high compression mode, that is, the separation indicating that the compression processing is performed selectively using the information output from the character representative color determination unit 37. The compression condition is associated and stored in the storage unit 12.

  Protocols related to data transfer to a printer or file system (including the storage unit 12 itself) such as LPR and FTP (file transfer protocol) include separation compression conditions for setting a high image quality mode, that is, selected data and smoothing. The separation / compression condition indicating that compression processing is selectively performed using the foreground data subjected to the conversion processing is stored in the storage unit 12 in association with each other.

  Thus, in the present embodiment, the number of planes to be output varies depending on the separation compression condition. That is, in the high image quality mode, three planes, that is, a selection data plane, a smoothed foreground data plane, and a background data plane are output. In the high compression mode, a group is output. A plane for each group rectangle generated for each representative color and a background data plane are output. Here, since the number of planes for each group rectangle depends on the number of character colors used in the original image data, the number of output planes is not necessarily three.

  In the above description, the example of separating the image of the character / line drawing part into groups for each representative color in the high compression mode as the separation compression condition has been described. However, compression processing such as further reducing the resolution is performed. Separation and compression conditions may be included. In this case, the selection unit 39 performs conversion for reducing the resolution based on the separation and compression condition and outputs the converted information, and also outputs information representing the original resolution.

  Further, the description so far has shown the case where the storage unit 35 is provided to reuse the data, but this storage unit 35 is not necessarily required. That is, the selection data, foreground data, and background data output from the isolated point removal unit 32, the multiplexer 33, and the hole filling processing unit 34 are converted into a character region detection unit 36, a character representative color determination unit 37, and a smoothing processing unit, respectively. 38, and may be directly output to the selection unit 39.

  That is, the image processing apparatus 1 according to the present embodiment operates as shown in FIG. First, the contents of the process designated for the image data to be processed are acquired (S1). For example, when the user gives an instruction to send image data by e-mail, the content of the process is specified as “e-mail transmission”. Here, the contents of the process are specifically identified by the type of protocol used in the data transfer process (for example, SMTP in the case of e-mail transmission). The contents of this processing may be accepted by presenting an interface as shown in FIG. 9, for example.

  Then, the image processing apparatus 1 generates so-called three-layer MRC data including selection data, foreground data, and background data based on each pixel of bitmap image data to be processed (S2).

  Next, the image processing apparatus 1 refers to the separation compression condition registered in advance in association with the content of the process acquired in the process S1, and checks whether it is a condition of “high image quality mode”. (S3). Here, if it is not “high image quality mode” (because it is one of two separation compression conditions in this embodiment), it is assumed that it is “high compression mode”, and the foreground data of the character / line drawing portion is based on the selected data. Is further multi-layered into color-specific data (S4). As a result, the image of the character / line drawing part is limited to a limited color, and is separated into each layer including information specifying the color and binary bitmap (and coordinate information indicating the arrangement position of the bitmap), and compressed. The rate is improved (because it is not a multi-valued image and becomes data consisting of a partial bitmap).

  Then, the image processing apparatus 1 performs compression processing on the multi-layered color-specific data and selection data generated in step S4, and the background data, respectively, a character / line drawing plane group for each color, a selection data plane, A background data plane is obtained (S5), these planes are combined to generate compressed data (S6), the compressed data is subjected to a designated process (S7), and the process ends. If the designated process is a process for transferring compressed data, the compressed data is transferred to the designated transfer destination.

  On the other hand, if it is “high image quality mode” in the processing S3, the selection data, foreground data and background data are respectively compressed (S8), and the selection data plane, foreground data plane and background data are compressed. The planes are obtained, these planes are combined to generate compressed data (S9), and the process proceeds to S7.

Note that the synthesis of the planes in steps S6 and S9 is, for example, PDF (Portable
Document Format). For example, in the high image quality mode, first, an instruction to decompress and draw the background data plane is described. Then, the foreground data plane and the selection data plane are expanded to selectively select only the pixels whose corresponding pixels are significant in the selection data from the pixels included in the foreground data. Describe the instruction to overwrite the data rendering result.

  As described above, according to the present embodiment, the compression rate is adjusted based on a predetermined condition in accordance with the content of the process by a simple operation for designating the process.

1 is a configuration block diagram of an image processing apparatus according to an embodiment of the present invention. It is a functional block diagram concerning an example of a program of an image processing device concerning an embodiment of the invention. It is a functional block diagram showing the example of the processing content of a separation compression part. It is explanatory drawing showing the process example of an isolated point removal process. It is explanatory drawing showing the example of isolation | separation of image data. It is explanatory drawing showing the example of the process multi-layered to the data according to color. It is explanatory drawing showing the process example of a hole filling process and a smoothing process. It is a flowchart figure showing an example of processing of an image processing device concerning an embodiment of the invention. It is explanatory drawing showing the example of the interface which receives the content of a process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image processing apparatus, 2 Scanner, 3 Printer, 11 Control part, 12 Storage part, 13 Operation part, 14 Display part, 15 Communication part, 16 Input / output interface, 21 Separation compression part, 22 Information acquisition part, 23 Output part, 31 binarization unit, 32 isolated point removal unit, 33 multiplexer, 34 hole filling processing unit, 35 storage unit, 36 character region detection unit, 37 character representative color determination unit, 38 smoothing processing unit, 39 selection unit.

Claims (5)

Means for receiving an instruction to transfer the image data to be processed to a designated transfer destination;
Determining means for deciding whether to compress the image data in a high image quality mode or a high compression mode based on a setting associated with the designated transfer destination;
Means for generating selection data representing pixels constituting a character / line drawing, performing layout analysis processing on the selection data, and extracting a character string region which is a layout element by layout analysis processing ;
When it is determined by the determination that the compression is performed in the high image quality mode, the designated data plane, the foreground data plane from which the portion represented by the selection data in the image data is extracted, and the background data plane are specified. Means for forwarding to a designated forwarding destination;
When it is determined by the determination that compression is performed in the high compression mode, foreground data in which a portion represented by the selection data is extracted from the image data for each character string region is generated, and for each character string region from the foreground data. to a group of characters, line drawings, which is determined as the same color, and the color quantization by determining a representative color for each the group, for each of the character string region group to which the generated for each representative color for each original Means for transferring the number of planes depending on the number of character colors used in the image data and the background data plane to the designated transfer destination;
An image processing apparatus comprising: The image processing apparatus according to claim 1,
The image processing apparatus, wherein the determining means determines whether to compress the image data in a high image quality mode or a high compression mode based on a protocol type related to the transfer process. The image processing apparatus according to claim 1,
The image processing apparatus, wherein the determining means determines whether to compress the image data in a high image quality mode or a high compression mode based on the address information of the transfer destination. Accept the instruction to transfer the image data to be processed to the specified transfer destination,
Determining whether to compress the image data in a high-quality mode or a high-compression mode based on a setting associated with the designated transfer destination;
Generates selection data representing pixels constituting the character / line drawing, performs layout analysis processing on the selection data, extracts a character string area that is a layout element by layout analysis processing,
When it is determined by the determination that the compression is performed in the high image quality mode, the designated data plane, the foreground data plane from which the portion represented by the selection data in the image data is extracted, and the background data plane are specified. To the specified transfer destination,
When it is determined by the determination that compression is performed in the high compression mode, foreground data in which a portion represented by the selection data is extracted from the image data for each character string region is generated, and for each character string region from the foreground data. to a group of characters, line drawings, which is determined as the same color, and the color quantization by determining a representative color for each the group, for each of the character string region group to which the generated for each representative color for each original An image processing method, wherein a number of planes depending on the number of character colors used in image data and a background data plane are transferred to the designated transfer destination. Computer
Means for receiving an instruction to transfer the image data to be processed to a designated transfer destination;
Determining means for deciding whether to compress the image data in a high image quality mode or a high compression mode based on a setting associated with the designated transfer destination;
Means for generating selection data representing pixels constituting a character / line drawing, performing layout analysis processing on the selection data, and extracting a character string region which is a layout element by layout analysis processing ;
When it is determined by the determination that the compression is performed in the high image quality mode, the designated data plane, the foreground data plane from which the portion represented by the selection data in the image data is extracted, and the background data plane are specified. Means for forwarding to a designated forwarding destination;
When it is determined by the determination that compression is performed in the high compression mode, foreground data in which a portion represented by the selection data is extracted from the image data for each character string region is generated, and for each character string region from the foreground data. to a group of characters, line drawings, which is determined as the same color, and the color quantization by determining a representative color for each the group, for each of the character string region group to which the generated for each representative color for each original Means for transferring the number of planes depending on the number of character colors used in the image data and the background data plane to the designated transfer destination;
A program characterized by functioning as

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